T cell receptors with MHC independent binding to GM-CSF receptor alpha chain

ABSTRACT

The present invention relates to novel tumor-associated antigens, which elicit independently from a presentation via MHC a CD8-positive T-cell response. GM-CSF-Receptor alpha chain (CSF2RA) and Tyrosinase-related protein 2 (TRP-2) were found to be targets of CD8-positive T-cell clones which could detect the proteins on the surface of HLA I negative melanoma cells. Thus, the invention provides proteins, protein fragments and polypeptides of the novel antigens for use in medicine, for example for the treatment, diagnosis and prevention of a tumor disease. Furthermore provided are nucleic acids expressing the antigens of the invention, binding agents specific for the antigens of the invention, such as T-cell receptor chains and isolated T cells which are reactive against the antigens of the invention or which express the T-cell receptors of the invention. The invention further pertains to pharmaceutical compositions, especially vaccine compositions, comprising the antigens, nucleic acids, binding agents or T cells in accordance with the invention, and methods for the generation of T cells, which are specifically reactive to the antigens of the invention in an MHC-independent manner.

CROSS REFERENCE TO A RELATED APPLICATION

This application is a National Stage Application of InternationalApplication Number PCT/EP2013/076760, filed Dec. 16, 2013; which claimspriority to European Application No. 12197289.7, filed Dec. 14, 2012;both of which are incorporated herein by reference in their entirety.

The Sequence Listing for this application is labeled“SEQ-LIST-5-28-15.TXT”, which was created on May 28, 2015, and is 26 KB.The entire content is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to novel tumor-associated antigens, whichelicit independently from a presentation via MHC a CD8 positive T-cellresponse. GM-CSF-Receptor alpha chain (CSF2RA) and Tyrosinase-relatedprotein 2 (TRP-2) were found to be targets of CD8 positive reactiveT-cell clones which could detect the proteins on the surface of HLA Inegative melanoma cells. Thus, the invention provides proteins, proteinfragments and polypeptides of the novel antigens for use in medicine,for example for the treatment, diagnosis and prevention of a tumordisease. Furthermore provided are nucleic acids expressing the antigensof the invention, binding agents specific for the antigens of theinvention, such as T-cell receptor chains and isolated T cells which arereactive against the antigens of the invention or which express theT-cell receptors of the invention. The invention further pertains topharmaceutical compositions, especially vaccine compositions, comprisingthe antigens, nucleic acids, binding agents or T cells in accordancewith the invention, and methods for the generation of T cellsspecifically reactive to the antigens of the invention in anMHC-independent manner.

DESCRIPTION

Cancer is still the main cause of death albeit the development of manytreatment strategies including extensive radiation and chemotherapy.Furthermore, it is known that tumor rejection mechanisms are mediated byautologous immune cells, especially T-cells, which are able todifferentiate between cancerous cells and healthy cells by the detectionof tumor-associated antigen (TAA)-fragments via major histocompatibilitycomplex (MHC) presentation. Antigens which are specifically expressed intumor cells and not in healthy tissue can be categorized into fourtypes: (I) mutated antigens develop during tumorigenesis by pointmutations or translocations within the tumor cells. Those antigens arestrictly tumor-specific. (II) cancer/germline antigens are usuallyexpressed solely within the germ cells of an adult organism and not inhealthy somatic tissue. In cancer cells, however, due to the loss ofepigenetic regulation, germ-cell specific genes can be activated. (III)differentiation antigens are expressed in tumors and their healthyprogenitor cells. CTL responses against such antigens often result inauto-immune reactions. (IV) overexpressed TAA show only minor expressionin healthy cells whereas in a tumor those antigens are stronglyactivated. Human tumors usually express antigens of different categoriesand might even process and present distinct peptides from each of theseproteins via their respective HLA class I and class II molecules.

MHC molecules in humans are normally referred to as HLA (human leukocyteantigen) molecules. There are two principal classes of HLA molecules:class I and class II. CD8-positive T cells are usually cytotoxic(therefore named cytotoxic T cells=CTL), recognize peptides of 9 to 10amino acids which are intracellularly processed from proteins of anysubcellular localization and which are presented on the cellular surfaceby HLA class I molecules. In the field of human cancer immunology, thelast two decades have seen intensive efforts to characterisecancer-associated and cancer-specific antigens. Also, effort has beendevoted to the analysis of antibodies to human tumor antigens. Suchantibodies can be used for diagnostic and therapeutic purposes, forinstance in combination with an anti-cancer agent. In addition,promising approaches of vaccine therapies are currently developed basedon MHC-class I antigenic fragments, there is still no satisfactoryimmune therapy available for most cancer types.

To date only few examples are known for HLA/MHC-independent recognitionof TAA via CD4- or CD8-positive T cells. Barnd and co-workers, 1989PNAS, described the recognition of epithelial mucin on breast andovarian cancer cells. A HLA-independent recognition was further fbundfor nickel-reactive CD8-positive T-cells in two patients suffering fromcontact dermatitis (Moulon et al., J Invest Dermatol 2003), for amelanoma-reactive T-cell clone without identifying the responsibleantigen (Somasundaram et al., J Transl Med 2005) and for a kidney cellcarcinoma-reactive T-cell clone (Wang et al., J Immunol 2008); theantigen of the latter was recently published (Hanada et al., Blood2011).

Although a high number of HLA-restricted TAAs out of all four of theabove mentioned categories were identified in the past, still nosatisfactory treatment based on a therapeutic vaccination and adoptivetransfer of antigen-specific T cells is available. This is in part dueto problems with respect to reproducibility of the results in clinicalstudies or to the observation of an only insufficient clinical effect ofthe vaccine. A problem often encountered in cancer immunotherapy isfurther an impairment of the immunogenicity in cancer tissue. Thisso-called “immune escape” can be understood on the basis of phenotypedifferences encountered in neoplastic cells. For example, tumor cellsshow decreased ability to process and present antigens, have a decreasedability to stimulate autologous T cells, show complete downregulation ofimmunogenic proteins associated with transformed cells and/or no or lowexpression of leukocyte adhesion molecules or other accessory moleculesand selective downregulation of certain MHC class I and class IIalleles. The latter may affect all class I/II antigens, or only part ofthem. Partial HLA loss of function or expression can be caused by lossof single HLA alleles, HLA haplotypes or complete HLA class I loss dueto bi-allelic β2m gene loss (Aptsiauri et al., Cancer Immunol Immunother2008; Bernal M. et al. Cancer Immunol Immunother 61:1359-71, 2012).Tumors that have lost the expression of HLA are thus resistant to anytreatment based on HLA-dependent T cells. Indeed, impairment of HLAfunction is one of the key “immune escape” mechanisms of tumor cells andthus limits the application of T-cell mediated immune therapy.

In view of the above described background art, the objective of thepresent invention is to provide novel tumor associated antigens (TAA)which allow for the development of novel treatments of cancer, andspecifically novel treatments that circumvent the problem of immuneescape in cancer cells.

In a first aspect of the present invention, the above objective issolved by providing a protein, protein fragment or polypeptidecomprising at least 8 contiguous amino acids from the amino acidsequence of the GM-CSF-receptor alpha chain (CSF2RA) (SEQ ID No. 1) orthe tyrosinase-related protein 2 (TRP-2) (SEQ ID No. 2), wherein saidprotein, protein fragment or polypeptide is capable of inducing a T-cellresponse and/or binding a cognate T-cell receptor.

In another embodiment of the invention, the protein, protein fragment orpolypeptide comprises the amino acid sequence of a complex epitope ofthe native TRP-2 or CSF2RA proteins. A complex epitope in connectionwith the herein described invention is a binding site for animmunological binding agent, such as a T-cell receptor (TCR) orantibody, which is composed of two or more amino acid sequences whichare in close spatial proximity in the native three-dimensional foldedproteins, but which do not constitute one contiguous sequence within thelinear amino acid sequence of the antigen. A complex epitope, forexample, can be composed of stretches of the amino acid sequences of twospatially closely folded secondary structures within the antigen, orbetween two separate amino acid chains of contacting subunits of a multiprotein complex.

The inventors surprisingly identified the proteins tyrosinase-relatedprotein 2 (TRP-2) and GM-CSF receptor alpha chain (CSF2RA) as moleculesexpressed in melanoma (TRP-2) and other malignant cell types (CSF2RA),which are recognized by T cells in an HLA-independent manner. Thus, Tcells against the antigens of the invention provide the surprisingadvantage to lyse tumors cells that are either completely negative forHLA class I expression, or at least show an impairment of HLA expressionand/or function. Normally such cells would escape the patient's naturalor a therapeutically induced immune rejection.

The protein, protein fragment or polypeptide of the invention in anadditional embodiment comprises at least 10, preferably 15, 20, 50, andmost preferably 100 contiguous amino acids from the amino acid sequenceof GM-CSF-Receptor alpha chain (CSF2RA) (SEQ ID No. 1) ortyrosinase-related protein 2 (TRP-2) (SEQ ID No. 2), wherein saidprotein, protein fragment or polypeptide is capable of inducing a T-cellresponse and/or binding a cognate T cell receptor.

In the context of the present invention the terms “protein” or“polypeptide” are used interchangeably and denote a polymer composed ofamino acid monomers joined by peptide bonds. A “peptide bond” is acovalent bond between two amino acids in which the α-amino group of oneamino acid is bonded to the α-carboxyl group of the other amino acid.All amino acid or polypeptide sequences, unless otherwise designated,are written from the amino terminus (N-terminus) to the carboxy terminus(C-terminus). The terms “protein”, “protein fragment” and “polypeptide”refer to a molecular chain of amino acids, and do not refer to aspecific length of the product and if required can be modified in vivoor in vitro, for example by glycosylation, amidation, carboxylation orphosphorylation. Thus, inter alia peptides, oligopeptides and proteinsare included within the definition of polypeptide.

Of course, functional derivatives and fragments of the polypeptide,summarized under the term “protein fragment”, are also included in thepresent invention. Functional derivatives are meant to includepolypeptides which differ in one or more amino acids in the overallsequence, which have deletions, substitutions, inversions, insertions oradditions. Amino acid substitutions which can be expected not toessentially alter biological and immunological activities, have beendescribed. Amino acid replacements between related amino acids orreplacements which have occurred frequently in evolution are inter aliaSer/Ala, Ser/Gly, Asp/Gly, Asp/Asn, Ile/Val.

In addition, the term “functional derivatives” of these polypeptidesalso implies the addition salts of the polypeptides, amides of thepolypeptides and specifically the C-terminal amides, esters andspecifically the C-terminal esters and N-acyl derivatives specificallyN-terminal acyl derivatives and N-acetyl derivatives.

In accordance with the present invention, the protein, protein fragmentor polypeptide is in a preferred embodiment a protein, protein fragmentor polypeptide comprising an amino acid sequence with at least 50%, 60%,70%, 80%, 90%, 95%, most preferably 99% and even more preferably 100%sequence identity to the amino acid sequence of the proteins GM-CSFreceptor alpha chain (CSF2RA) or tyrosinase-related protein 2 (TRP-2),specifically to the amino acid sequences as shown in SEQ ID No. 1 or 2.

In preferred embodiments protein fragments of the herein describedantigens are immunogenic fragments, which still have the ability toinduce an immunogenic response, preferably independent of MHC class Iand/or II.

In preferred embodiments of the invention the protein, protein fragmentor polypeptide consists of the amino acid sequence shown in SEQ ID No. 1or 2.

The polypeptides according to the invention can be produced eithersynthetically or by recombinant DNA technology. Methods for producingsynthetic polypeptides are well known in the art.

With the aid of the proteins, protein fragments or polypeptides inaccordance with the invention cytotoxic and helper T cells can begenerated, which develop an antigen-specific, MHC-independent cytotoxicactivity against tumor cells expressing proteins, protein fragments orpolypeptides of the invention and destroy them. Therefore, thesepolypeptides open up the possibility of an effective tumor therapy, inthe course of which the suppression of an immune reaction, which isoften observed in tumor patients, can be reversed.

The invention also relates to a fusion protein composed of one of theaforementioned proteins, protein fragments or polypeptides and of asecond protein or polypeptide. Such fusion proteins are suitable for useas a diagnostic or therapeutic or prophylactic agent or generally for adetection and/or manipulation of T cells that recognize TRP-2 or CSF2RA,specifically independent of their presentation via MHC. For example,fusion proteins could be envisioned that consist of a carrier proteinsuch as, for example, HSA, collagen or other proteins and one or more ofthe polypeptides of the invention. The polynucleotides coding for thisfusion protein are also the subject matter of the present invention.

Further provided is the protein, protein fragment or polypeptide inaccordance with the present invention, which is characterized by thepresence of a signal peptide which mediates the cellular transport ofthe molecule, when expressed in a cell, to the outside of the cellularmembrane. Signal peptides are known to the person of skill in the art.More preferably the protein, protein fragment or polypeptide inaccordance with the present invention comprises a domain capable ofanchoring the molecule of the invention to the cellular membrane. Such adomain could be a membrane anchor or a transmembrane domain.

In one embodiment the protein, protein fragment or polypeptide accordingto the invention is characterized in that it is capable of inducing amajor histocompatibility complex (MHC) independent T-cell response,preferably a MHC class I independent T-cell response, or a MHC class Iand II independent T-cell response; and/or the protein, protein fragmentor polypeptide is characterized in that it is capable of binding acognate T-cell receptor expressed by a MHC class I independent T cell ora MHC class I and II independent T cell.

Due to the surprising finding of the independence of the recognition ofthe molecules of the invention from HLA/MHC expression, it is onefurther preferred embodiment that the protein, protein fragment orpolypeptide in accordance with the invention is not presented by MHCclass I, or MHC class I and II. The protein, protein fragment orpolypeptide of the invention is preferably expressed on the cellularsurface without undergoing a fragmentation as it is known for thepresentation of MHC-restricted antigens. Thus, the present inventionshall in a preferred embodiment pertain to such a protein, proteinfragment or polypeptide which, when expressed in an HLA/MHC-negativecell, still is able to induce a T-cell response.

In the context of the various embodiments described herein, a protein,protein fragment or polypeptide shall not be excluded from the scope ofthe invention just because in addition to its capability to mediate aHLA-independent T-cell response, it still can be processed and presentedby the MHC/HLA pathway. Only in specific embodiments of the invention aprotein, a protein fragment or polypeptide shall be excluded, when itconsists of an MHC/HLA class I and/or II binding epitope.

One particularly preferred embodiment of the present invention relatesto the protein, protein fragment or polypeptide according to thedescription herein before, for use in medicine, specifically for use ina method of treatment of the human or animal body by surgery or therapy,or diagnostic methods practised on the human or animal body.

Further provided according to the present invention is the protein,protein fragment or polypeptide as described herein, for use in theprevention, diagnosis or treatment of a proliferative disease,preferably wherein the proliferative disease is a tumor disease. Apreferred tumor disease according to the invention is a tumor diseasethat is devoid of a functional MHC class I complex, or that is devoid offunctional MHC class I and II complexes, specifically such tumors whichdo not express MHC class I, or do not express MHC class I and II. Hence,the protein, protein fragment or polypeptide as described herein arespecifically for use in the prevention, diagnosis or treatment of atumor which exhibit immune escape by alteration of the MHC class Iand/or II presentation complex.

As used herein, the term “tumor” or “tumor disease” means both benignand malignant tumors or neoplasms and includes melanomas, lymphomas,leukemias, and sarcomas, illustrative examples of tumor tissues arecutaneous such as malignant melanomas and mycosis fungoides; hematologictumors such as leukemias, for example, acute lymphoblastic, acutemyelocytic, or chronic myelocytic leukemia; lymphomas such as Hodgkin'sdisease or malignant lymphoma; gynecologic tumors such as ovarian anduterine tumors; urologic tumors such as those of the prostate, bladder,or testis; soft tissue sarcomas, osseus, or non-osseous sarcomas, breasttumors; tumors of the pituitary, thyroid, and adrenal cortex;gastrointestinal tumors such as those of the esophagus, stomach,intestine, and colon; pancreatic and hepatic tumors; laryngealpapillomas/carcinomas and lung tumors.

In preferred embodiments the tumor to be treated, diagnosed or preventedis characterized by the expression of CSF2RA (SEQ ID No 1) and/or TRP-2(SEQ ID No 2). Or tumors expressing homologs of the aforementionedantigens, wherein a homolog is characterized the sequence identity of atleast 75, preferably 80, 90, or 95% compared to a sequence as shown inSEQ ID No. 1 or 2, respectively.

Furthermore, such tumors are preferred in accordance with the variousembodiments of the invention which underwent, or are at risk ofundergoing, immune escape mechanisms by altering the expression and/orfunction of the HLA complexes (either class I or II or both) within thetumor cell.

Preferred tumors of the present invention with respect of TRP-2 aretumors of the skin, preferably melanoma, or tumors of the centralnervous system, preferably glioblastoma.

On the other hand preferred tumors (or malignancies) of the presentinvention with respect to CSF2RA are tumors of the skin, such asmelanoma, hematological malignancies expressing CSF2RA, such asleukemia, and solid tumors expressing CSFRA, such as lung cancer,pancreatic cancer, colorectal cancer and ovarian cancer. Specificallypreferred in another embodiment is that the malignancy which expressesCSF2RA does not express CSF2RB, or expressed CSF2RB to a significantlylower level than CSF2RA.

In a preferred embodiment of the present invention, the above describedprotein, protein fragment or polypeptide of the invention for use inmedicine, or proteins used within the herein described specific methods,are the full length proteins of CSF2RA and/or TRP-2, possible with minoramino acid changes of preferably not more than 50, 40, 30, 20,preferably 10, most preferably 5 amino acid residues compared to thesequences shown in SEQ ID No. 1 or 2, respectively. Such sequencechanges can be additions, deletions, substitutions, inversions,insertions or chemical modification of one or more amino acid residues.

In an additional aspect, the present invention further provides anisolated nucleic acid molecule, wherein said nucleic acid molecule (a)has a strand encoding for a protein, protein fragment or polypeptideaccording to the invention; (b) has a strand complementary to the strandin (a); or (c) has a strand that hybridizes under stringent conditionswith a molecule as described in (a) or (b). Stringent conditions areknown to the person of skill in the art, specifically from Sambrook etal, “Molecular Cloning”. In addition to that, the nucleic acidoptionally has further sequences which are necessary for expressing thenucleic acid sequence corresponding to the protein, specifically forexpression in a mammalian/human cell. The nucleic acid used can becontained in a vector suitable for allowing expression of the nucleicacid sequence corresponding to the peptide in a cell. However, thenucleic acids can also be used to transfect a presenting cell, whichshall not be restricted to classical antigen-presenting cells such asdendritic cells, in such a way that they themselves produce thecorresponding proteins on their cellular surface.

The nucleic acid molecules of the invention are preferably for use inmedicine.

Also provided is a vector or a cell comprising a nucleic acid moleculedescribed herein above, specifically wherein the vector is for use inmedicine. Also a cell comprising a vector according to the invention isprovided.

Another aspect of the present invention is the use of at least oneprotein, protein fragment or polypeptide in accordance with theinvention or a nucleic acid in accordance with the invention foreliciting an immune reaction in connection with a tumor therapy or atreatment for preventing a tumor. Advantageous here is the fact that thefrequently observed immune escape mechanisms and tolerance to TAA in atumor disease can be overcome (or reversed) by the use of a protein,protein fragment or polypeptide, or nucleic acids in accordance with theinvention. The use in accordance with the invention can also be employedin addition to established tumor therapies.

A preventive treatment in the context of the herein described inventionis of benefit possibly mainly to persons who have an increased risk ofdeveloping a tumor, because, for example, they are hereditarilypredisposed or because they have already had a tumor before. In anotherembodiment a preventive treatment is of benefit for a patient sufferingfrom a tumor disease with increased risk of having developed ordeveloping resistance to immune rejection, by e.g. immune escape via thealteration of the function and/or expression of HLA class I/IIcomplexes.

Yet another aspect of the invention pertains to a binding agent, whichbinds to a protein, protein fragment or polypeptide as described hereinabove, preferably wherein the binding agent is specific for saidprotein, protein fragment or polypeptide. In preferred embodiments thebinding agents as described herein are for use in medicine.

In one embodiment the binding agent according to the invention is anantibody, or a fragment thereof. The term “antibody” in its variousgrammatical forms is used herein to refer to immunoglobulin moleculesand immunologically active portions of immunoglobulin molecules, i.e.,molecules that contain an antibody combining site or a paratope. Suchmolecules are also referred to as “antigen binding fragments” ofimmunoglobulin molecules. Illustrative antibody molecules are intactimmunoglobulin molecules, substantially intact immunoglobulin moleculesand those portions of an immunoglobulin molecule that contain theparatope, including those portions known in the art as Fab, Fab′,F(ab′)2 and F(v). Antibodies of the present invention may be monoclonalor polyclonal. The term antibody is also intended to encompass singlechain antibodies, chimeric, humanized or primatized (CDR-grafted)antibodies and the like, as well as chimeric or CDR-grafted single chainantibodies, comprising portions from two different species.Immunological adjuvants for vaccines comprising lecithin may be used tostimulate antibody production.

In another embodiment the binding agent of the invention is a T-cellreceptor (TCR), or a fragment thereof. A TCR is a heterodimeric cellsurface protein of the immunoglobulin superfamily which is associatedwith invariant proteins of the CD3 complex involved in mediating signaltransduction. TCRs exist in αβ and γδ forms, which are structurallysimilar but have quite distinct anatomical locations and probablyfunctions. The extracellular portion of native heterodimeric αβTCRconsists of two polypeptides, each of which has a membrane-proximalconstant domain, and a membrane-distal variable domain. Each of theconstant and variable domains includes an intra-chain disulfide bond.The variable domains contain the highly polymorphic loops analogous tothe complementarity determining regions (CDRs) of antibodies.

In one preferred embodiment the TCR of the invention is characterized tocomprise a sequence according to any one of SEQ ID No. 3 to 8, or havinga sequence that is at least 75, preferably 80, 90, or 95% identical anyone of SEQ ID No. 3 to 8. Also comprised are T cells which express TCRshaving a sequence according to any one of SEQ ID No. 3 to 8, or having asequence that is at least 75, preferably 80, 90, or 95% identical to SEQID No. 3 to 8.

An antigen binding agent of the invention, preferable a TCR or antibody,is in one embodiment characterized by the presence of any one of, orpreferably all, CDR 1 to 3 sequences as depicted for the respectivealpha or beta chains of the TCRs of the invention in the figures andtable 1 below. In this embodiment it is also preferred that the TCR ofthe invention is a chimerized TCR, for example, by exchanging completelyor in part the original human constant domain with a murine constantdomain (see FIG. 13). A preferred murinization of the constant domain isthe exchange of at least the extracellular part of the constant domainwith murine sequences.

One embodiment of the present invention pertains to an antigen bindingpolypeptide comprising at least one CDR sequences, preferably CDR3, morepreferably CDR1, CDR2 and CDR3, of any one of the TCR as isolated incontext of the present invention and as depicted in table 1 below.

TABLE 1 CDR sequences of the T-cell receptor clones of the invention.SEQ ID NO are given in ( ): Target TCR Chain: CDR1 CDR2 CDR3 CSF2RA1A.1/506 alpha DSAIYN(9) IQSSQRE(10) CAVGGNDYKLS(11) CSF2RA1A.1/506 beta ENHRY(12) SYGVKD(13) CAISEKLAGAYEQY(14) TRP2 2C/417 alphaVSGNPY(15) YITGDNLV(16) CAVRDMIEGGGNKLT(17) TRP2 2C/417 beta MDHEN(18)SYDVKM(19) CASSRQGAVGQPQH(20) CSF2RA 1A3/46 alpha TSDPSYG(21)QGSYDQQN(22) CAMRPHFGNEKLT(23) CSF2RA 1A3/46 beta ENHRY(24) SYGVKD(25)CAISEKLAGAYEQY(26)

The antigen binding polypeptide of the invention is preferably a TCR.

Thus also preferred is a T cell receptor alpha chain comprising any one,or all of, of the SEQ ID NO: 9 to 11, or 15 to 17, or 21 to 23.

Thus also preferred is a T cell receptor beta chain comprising any one,or all of, of the SEQ ID NO: 12 to 14, or 18 to 20, or 24 to 26.

Preferably a T-cell receptor of the invention, or a binding fragmentthereof, has an alpha chain variable region comprising the CDR sequencesof SEQ ID NO: 9, 10 and/or 11, and a beta chain variable regioncomprising the CDR sequences of SEQ ID NO: 12, 13 and/or 14. Such a TCRis a TCR specific for the antigen CSF2RA. Preferably this TCR is the TCRas isolated from the CTL 1A.1/506 as described herein in the examples.Such a receptor may in one embodiment comprise the at least variableregion, preferably full length, sequence according to SEQ ID No. 3(alpha chain) and 4 (beta chain).

Preferably a T-cell receptor of the invention, or a binding fragmentthereof, has an alpha chain variable region comprising the CDR sequencesof SEQ ID NO: 21, 22 and/or 23, and a beta chain variable regioncomprising the CDR sequences of SEQ ID NO: 24, 25 and/or 26. Such a TCRis a TCR specific for the antigen CSF2RA. Preferably this TCR is the TCRas isolated from the CTL 1A3/46 as described herein in the examples.Such a receptor may in one embodiment comprise the at least variableregion, preferably full length, sequence according to SEQ ID No. 7(alpha chain) and 8 (beta chain).

Preferably a T-cell receptor, or a binding fragment thereof, has analpha chain variable region comprising the CDR sequences of SEQ ID NO:15, 16 and/or 17, and a beta chain variable region comprising the CDRsequences of SEQ ID NO: 18, 19 and/or 20. Such a TCR is a TCR specificfor the antigen TRP2. Preferably this TCR is the TCR as isolated fromthe CTL 2C/417 as described as described herein in the examples. Such areceptor may in one embodiment comprise the at least variable region,preferably full length, sequence according to SEQ ID No. 5 (alpha chain)and 6 (beta chain).

Yet another embodiment of the invention pertains to a single chain TCR(scTCR) as a binding agent, preferably an αβ-scTCR. Single-chain TCRs(scTCRs) are artificial constructs consisting of a single amino acidstrand. An scTCR can comprise a polypeptide of a variable region of afirst TCR chain (e.g., an [alpha] chain) and a polypeptide of an entire(full-length) second TCR chain (e.g., a [beta] chain), or vice versa.Furthermore, the scTCR can optionally comprise one or more linkers whichjoin the two or more polypeptides together. The linker can be, forinstance, a peptide which joins together two single chains, as describedherein. Such a scTCR may be composed of any of the variable and/orconstant region as provided herein.

Also provided is such a scTCR of the invention, which is fused to ahuman cytokine, such as IL-2, IL-7 or IL-15.

The binding agent according to the invention can also be provided in theform of a multimeric complex, comprising at least two scTCR molecules,wherein said scTCR molecules are each fused to at least one biotinmoiety, and wherein said scTCRs are interconnected by biotin-strepavidininteraction to allow the formation of said multimeric complex. Alsoprovided are multimeric complexes of a higher order comprising more thantwo scTCR of the invention.

In another preferred embodiment the binding agents of the invention is abi-specific monoclonal antibody comprising the binding fragments of anantibody as described herein above, and the binding fragments of asecond antibody which is, for example, specific for CD3.

Another aspect of the present invention pertains to a nucleic acidencoding a TCR or antigen binding agent as described herein.

In a further aspect, the objective of the present invention is solved byproviding a T cell which is reactive against any one of the proteins,protein fragments or polypeptides according to the invention,specifically against CSF2RA or TRP-2. In a preferred embodiment, theT-cell of the invention is reactive against the protein, proteinfragment or polypeptide according to the invention independent of thepresentation of said protein, protein fragment or polypeptide by MHCclass I and/or class II. An even more preferred embodiment of theinvention provides a T cell comprising a T-cell receptor (TCR) whichbinds to a protein, protein fragment or polypeptide according to theinvention, and wherein said binding is independent of the presentationof said polypeptide by MHC class I or MHC class I and II. The T cell ofthe invention is preferably CD8 and/or CD4 positive.

Further provided according to the present invention is the use of aprotein, protein fragment or polypeptide as described above, a nucleicacid as described above, a vector or cell as described above, a bindingagent as described above, a T cell as described above, a multimericcomplex as described above, in the preparation of a medicament fortreating cancer, or in the preparation of a diagnostic for diagnosingcancer. The cancer may be a mammalian cancer. In particular, the cancermay be human cancer. For example, the cancer may be breast cancer,prostate cancer, pancreatic cancer, colorectal cancer, lung cancer,malignant melanoma, leukaemia, lymphoma, ovarian cancer, cervical canceror a biliary tract carcinoma. Specifically preferred cancers aremelanoma, glioblastoma or leukemia. Said medicament may be a vaccine.

In another aspect the objective of the invention is further solved by anin-vitro method for generating MHC-independent T-cells, comprising thesteps of

-   -   i. providing a first cell, preferably a tumor cell, that        expresses a protein, protein fragment or polypeptide according        to the invention as described herein above, preferably wherein        the polypeptide is a full-length CSF2RA or TRP-2,    -   ii. bringing a population of peripheral blood mononuclear cells        (PBMCs) into contact with said first cell, and thereby        stimulating said PBMCs, and    -   iii. selecting out of the population of stimulated PBMCs T cells        which have the ability to recognize (or which are reactive        against) a cell expressing the protein, protein fragment or        polypeptide used in (i), independent of the expression of MHC in        said cell.

In this aspect, the MHC is preferably MHC class I and/or class II.

In one preferred embodiment of the method described above, said tumorcell and said PBMCs are autologous cells derived from one tumor patient.This embodiment has the advantage that MHC independent T cells can begenerated for a tumor patient. Such T cells are usable for re-injectioninto the patient as a treatment-agent against the tumor the patient issuffering from.

The above described method in one preferred embodiment comprises as saidfirst cell a cell that does not express MHC class I, or MHC class I andII, or that is at least impaired in MHC class I and/or II functionand/or expression.

Yet a further preferred embodiment of the above described method is,when in step (iii) said ability of a T cell to recognize a cellexpressing the protein, protein fragment or polypeptide used in (i)independent of the expression of MHC in said cell, is determined bytesting the reactivity of said T cell against said cell expressing theprotein, protein fragment or polypeptide, wherein

-   -   (a) said cell expressing the protein, protein fragment or        polypeptide is devoid of MHC class I or MHC class I and II,        and/or    -   (b) said T cell is tested for its reactivity against said cell        expressing the protein, protein fragment or polypeptide in the        presence of antibodies against MHC class I or II; and/or    -   (c) said T cell is tested for its reactivity against xenogenic        cells transfected with DNA or RNA encoding the protein, protein        fragment or polypeptide,        wherein in (a), (b) and/or (c) a T cell that shows reactivity is        a T cell having the ability to recognize a cell expressing the        protein, protein fragment or polypeptide used in (i) independent        of the expression of HLA/MHC in said cell.

Also provided are T cells which are generated by a method according tothe invention as described herein above. Preferably, the T cell of theinvention is for use in medicine. Specifically, the T cell of theinvention is for treating a patient suffering from a malignant diseaseby infusing said T cells into said patient, preferably wherein said Tcells are derived from autologous PBMCs of said patient.

A further aspect pertains to a pharmaceutical composition, comprising aprotein, protein fragment or polypeptide according to the invention, ora nucleic acid, a vector, a cell, a binding agent or an isolated T cellaccording to the invention. In a preferred embodiment the pharmaceuticalcomposition is a vaccine.

Examples of pharmaceutically acceptable carriers or diluents useful inthe present invention include stabilizers such as SPGA, carbohydrates(e.g. sorbitol, mannitol, starch, sucrose, glucose, dextran), proteinssuch as albumin or casein, protein containing agents such as bovineserum or skimmed milk and buffers (e.g. phosphate buffer).

Optionally, one or more compounds having adjuvant activity may be addedto the vaccine. Suitable adjuvants are, for example, aluminiumhydroxide, phosphate or oxide, oil-emulsions (e.g. of Bayol F<(R)> orMarcol 52<(R)>), saponins or vitamin-E solubilisate.

The vaccine according to the present invention can be given inter aliaintravenously, intraperitoneally, intranasally, intradermally,subcutaneously or intramuscularly.

The useful effective amount to be administered will vary depending onthe age and weight of the patient and mode of administration of thevaccine.

The vaccine can be employed to specifically obtain a T-cell response,but it is also possible that a B-cell response is elicited aftervaccination. If so, the B-cell response leads to the formation ofantibodies against the protein, protein fragment or polypeptide of thevaccine, which antibodies will be directed to the source of the antigenproduction, i.e. the tumor cells. This is an advantageous feature,because in this way the tumor cells are combated by responses of boththe cellular and the humoral arm of the immune system.

Both arms of immunological defense will even be more effectivelytriggered when the vaccine comprises the antigens of the invention in anantigen-presenting cell, independent of MHC expression. Antigenpresentation can be achieved by using monocytes, macrophages,interdigitating cells, Langerhans cells and especially dendritic cells,loaded with one of the antigens of the invention.

It is also possible to use cells already transfected with a cloningvehicle harbouring the information for the antigens of the invention.These cells will act as antigen-presenting cells and will present thefull-length antigens of the invention, or fragments thereof, on theirsurface in an MHC-independent manner. Thus, in the context of thepresent invention it is preferred to express the antigens of theinvention such, that they are transported to the cellular surface of theantigen-presenting cell.

Instead of a vaccination with these cells, which next to the desiredexpression products also harbour many elements which are also expressedand which can negatively affect the desired immunogenic reaction of thecell, it is also possible that a vaccine is composed of liposomes whichare loaded with the proteins, protein fragments and polypeptides of theinvention, and which thus expose these antigens to the host immunesystem. Such liposomes, for instance, are filled with lymphokines. Suchliposomes will trigger an immunological T-cell reaction.

By presenting the protein, protein fragment or peptide in the same wayas it is also presented in vivo, an enhanced T-cell response will beevoked. Furthermore, by the natural adjuvant working of the relativelylarge antigen-presenting cells also a B-cell response is triggered.

This B-cell response will a.o. lead to the formation of antibodiesdirected to the native antigen. This complex is especially fbund intumor cells, where it has been shown that the antigens of the inventionare presented naturally, which are thus able to elicit a T-cellresponse. It is this naturally occurring phenomenon which is enlarged bythe vaccination with cells already presenting the proteins, proteinfragments or peptides of the invention. By enlarging not only anenlarged T-cell response will be evoked, but also a B-cell response willbe initiated which leads to antibodies directed against theMHC-independent peptide.

The vaccines according to the invention can be enriched by numerouscompounds which have an enhancing effect on the initiation and themaintenance of both the T-cell and the B-cell response aftervaccination.

In this way addition of cytokines to the vaccine will enhance the T-cellresponse. Suitable cytokines are for instance interleukins, such asIL-2, IL-4, IL-7, IL-15 or IL-12, GM-CSF, RANTES, tumor necrosis factorand interferons, such as IFN-α, -β, or -γ.

In a similar way, antibodies against T-cell surface antigens, such asCD2, CD3, CTLA-4, PD-1, CD27 and CD28 will enhance the immunogenicreaction.

Also the addition of helper epitopes to stimulate CD4<+> helper cells orCD8<+> killer cells augments the immunogenic reaction. Alternativelyalso helper epitopes from other antigens can be used, for instance fromheat shock-derived proteins or cholera toxin.

Finally, the present invention relates to a method of treating a patientsuffering from a tumor disease, comprising the administration of atherapeutically effective amount of at least one protein, proteinfragment or polypeptide in accordance with the invention and/or at leastone nucleic acid and/or at least one binding agent and/or at least onevector molecule and/or at least one T cell of the invention in an amountsufficient to achieve a therapeutic effect. Another aspect is a methodof eliciting a tumor-specific CTL response comprising the administrationof a response-eliciting amount of the MHC independent antigens inaccordance with the invention (the proteins, protein fragments andpolypeptides of the invention). Target malignancies are those expressingCSF2RA and TRP-2.

The present invention will now be further described in the followingexamples with reference to the accompanying figures and sequences,nevertheless, without being limited thereto. For the purposes of thepresent invention, all references as cited herein are incorporated byreference in their entireties. In the Figures and Sequences:

FIG. 1: HLA class I-phenotyping of melanoma cell lines MA-MEL-86A, -86B,-86C und -86F, generated from distinct lymph node metastases of patientMA-MEL-86 (schematic representation). MEL-86A expresses all HLA class Ialleles of the patient but turned out to be negative for the expressionof melanocyte differentiation antigens. Bi-allelic inactivations of thebeta2-microglobulin (β2m) genes due to different mutations resulted in acomplete loss of surface expression of HLA molecules in MA-MEL-86B and-F. MA-MEL-86C has lost expression of one (the “blue”) HLA class Ihaplotype.

FIG. 2: Recognition of different MA-MEL-86 melanoma lines byindependently generated Mixed Lymphocyte-Tumor cell Cultures (MLTC).Several different MLTCs were generated by stimulation of peripheralblood mononuclear cells (PBMC) with either melanoma line MA-MEL-86A (A)or -86C (B). MLTC responders (20.000/well) were then tested forrecognition of MA-MEL-86A, -86B and -86C (50.000 cells/well) as well ascontrol cell lines by use of 20h-IFN-γ-ELISpot-Assays.

FIG. 3: cDNA-library-screening using MLTC 1A.1. MLTC 1A.1 was applied tothe screening of the cDNA expression library constructed from theMA-MEL-86A cell line. Left part: Pictures show magnified sections ofELISpot plates containing positive wells. Right part: Diagrams showingthe results of the analyses of the assays. (A) Section of the ELISpotplate testing of pools of 100 cDNAs per well comprising pools #701-796.After co-transfection of these cDNA pools together with HLA-A*24:02-cDNAinto 293T cells, MLTC 1A.1 recognized transfectants expressing pool #709(red circle). Pools of 10 cDNAs per well derived from 100× pool #709tested in the same way identified pools #39 and #51 as being recognizedby the T cells (B). Pool #39 was chosen for further subcloning. Thesubsequent testing of cDNA clones 709.39.1 to 709.39.96 identifiedcDNA-clone #18 as being recognized by MLTC 1A.1 (C). Targets: 293T cells(20.000 cells/well), MA-MEL-86A (50.000 cells/well); T cells: MLTC 1A.1(10.000 lymphocytes/well); transfected cDNAs: HLA-cDNA (100 ng/well);cDNA pools (300 ng/well); 20h-IFN-γ-ELISpot-Assay. Sequencing of cDNAclone #709.39.18 and Blast search with the derived sequences identifiedCSF2RA (the alpha chain of the GM-CSF-receptor) as recognized antigen.The 1.831 bp long ORF of the #709.39.18-cDNA encodes for the transcriptvariant 2 of the gene, the translation of which results in the isoform Aof the CSF2RA protein.

FIG. 4: Responses of CSF2RA-reactive CTL 1A.1/506 to different myeloidcells isolated from Buffy Coats (BC) of healthy donors. CTL 1A.1/506(40,000 cells/well) was tested for recognition of Monocytes,Granulocytes and Dendritic cells (DC) (50,000 cells/well), the latterisolated and differentiated in vitro from PBMC of BC of four differenthealthy donors. The autologous melanoma lines served as controls.

FIG. 5: Recognition of cells of various species after transfection withCSF2RA by CTL 1A.1/506. Human (K562, 293T), monkey (COS-7), and chinesehamster ovary (CHO) cells were transiently transfected with CSF2RA andtested for recognition by CTL 1A.1/506 using the IFN-γ ELISpot assay.All reactions were tested in duplicates.

FIG. 6: Tumor recognition by CTL 1A.1/506 with and without blockingantibodies.

CTL 1A.1/506 (10.000 cells/well) was tested with an IFN-γ-ELISpot-assayfor the recognition of MA-MEL-86B (50.000 cells/well). Monoclonalantibodies (mAbs) specific for pan-HLA I, CD3 or CSF2RA were applied toblock recognition. Only mAbs binding to CSF2RA or the T-cell receptor(CD3) inhibited the CTL response.

FIG. 7: Cloning of the T-cell receptor (TCR) of CTL 1A.1/506. Cloning ofthe TCR α- and β-chains was done according to the protocol published byBirkholz et al. (J Immunol Meth, 2009). TCR cDNA clones were sequencedand analyzed using the IMGT/VQuest database. TCR beta chains arecomposed of V (Variability)-, D (Diversity)- and J (Joining)-segments,while alpha chains are made up by V and J regions only. CDR(complementarity determining regions).

FIG. 8: Recognition of cells of various species after transfection withTRP-2 by CTL 2C/417. Human (K562, 293T, L721.221), monkey (COS-7), mouse(RMA/A2 #7, P815-TK-), and chinese hamster ovary (CHO) cells weretransiently transfected with TRP-2 and tested for recognition by CTL2C/417 using the IFN-γ ELISpot assay. All reactions were tested induplicates.

FIG. 9: Detection of TRP-2 surface expression by Confocal Laser ScanningMicroscopy. 293T cells transfected with plasmids encoding membrane-boundpEYFP-Mem (a) and human TRP-2 were cultured on microscope slides. TRP-2was detected with an Alexa 564-labeled polyclonal antibody against TRP-2(b). The 3D confocal picture revealed that TRP-2 was detected as atransmembrane protein by this antibody (c).

FIG. 10: Detection of TRP-2 surface expression by Confocal LaserScanning Microscopy using a TRP-2-α-BTX fusion protein. The 13 aminoacids long α-BTX binding site binds α-Bungarotoxin with high affinity.An α-BTX-binding site encoding sequence was integrated at differentpositions in the sequence coding for the extracellular portion of TRP-2(A). MA-MEL-86A cells, cultured on microscope slides, were transientlyco-transfected with a plasmid encoding the cell membrane trackingreagent pEYFP-Mem (a) and the TRP-2/αBTX-fusion protein. After stainingwith fluorescently labeled α-Bungarotoxin (red fluorescence, b), andoverlaying the two pictures, the cell surface expression of the fusionprotein became evident (yellow fluorescence, c).

FIG. 11: Recognition of TRP-2 by CTL 2C/417 requires that the proteincontains a transmembrane domain (TMD). Full length (fl) TRP-2 cDNA or aTRP-2 variant lacking the TMD-coding sequence of the protein (TMDdel)were transfected into 293T cells and tested for recognition by CTL2C/417 via the IFN-γ ELISpot assay. The deletion variant was notrecognized (A). When the original TMD-coding sequence was replaced bythe TMD cloned from the HLA-A24-cDNA and this replacement variant wastransfected in comparison with the TRP-2 fl-cDNA into 293T cells, theCTL recognized both variants (B). This result further confirms thatTRP-2 needs to be displayed on the cell surface to become recognized bythe T cells. (C) Schematic representation of the recombinant TRP-2containing the HLA-A24-TMD.

FIG. 12: Cloning of the T cell receptor (TCR) of CTL 2C/417. Cloning ofthe TCR α- and β-chains was done according to the protocol published byBirkholz et al. (J Immunol Meth, 2009). TCR cDNA clones were sequencedand analyzed using the IMGT/VQuest database. TCR beta chains arecomposed of V (Variability)-, D (Diversity)- and J (Joining)-segments,while alpha chains are made up by V and J regions only. CDR(complementarity determining regions).

FIGS. 13A-13C: shows cloning expression and analysis of a native andchimerized TCR isolated from CTL 1A.3/46.

SEQ ID NO. 1 shows the amino acid sequence of CSF2RA:

MLLLVTSLLLCELPHPAFLLIPEKSDLRTVAPASSLNVRFDSRTMNLSWDCQENTTFSKCFLTDKKNRVVEPRLSNNECSCTFREICLHEGVTFEVHVNTSQRGFQQKLLYPNSGREGTAAQNFSCFIYNADLMNCTWARGPTAPRDVQYFLYIRNSKRRREIRCPYYIQDSGTHVGCHLDNLSGLTSRNYFLVNGTSREIGIQFFDSLLDTKKIERFNPPSNVTVRCNTTHCLVRWKQPRTYQKLSYLDFQYQLDVHRKNTQPGTENLLINVSGDLENRYNFPSSEPRAKHSVKIRAADVRILNWSSWSEAIEFGSDDGNLGSVYIYVLLIVGTLVCGIVLGFLFKRFLRIQRLFPPVPQIKDKLNDNHEVEDEIIWEEFTPEEGKGYREEVLTVKEIT

SEQ ID NO. 2 shows the amino acid sequence of TRP-2 (isoform 1)

MSPLWWGFLLSCLGCKILPGAQGQFPRVCMTVDSLVNKECCPRLGAESANVCGSQQGRGQCTEVRADTRPWSGPYILRNQDDRELWPRKFFHRTCKCTGNFAGYNCGDCKFGWTGPNCERKKPPVIRQNIHSLSPQEREQFLGALDLAKKRVHPDYVITTQHWLGLLGPNGTQPQFANCSVYDFFVWLHYYSVRDTLLGPGRPYRAIDFSHQGPAFVTWHRYHLLCLERDLQRLIGNESFALPYWNFATGRNECDVCTDQLFGAARPDDPTLISRNSRFSSWETVCDSLDDYNHLVTLCNGTYEGLLRRNQMGRNSMKLPTLKDIRDCLSLQKFDNPPFFQNSTFSFRNALEGFDKADGTLDSQVMSLHNLVHSFLNGTNALPHSAANDPIFVVLHSFTDAIFDEWMKRFNPPADAWPQELAPIGHNRMYNMVPFFPPVTNEELFLTSDQLGYSYAIDLPVSVEETPGWPTTLLVVMGTLVALVGLFVLLAFLQYRRLRK GYTPLMETHLSSKRYTEEA

SEQ ID NO. 3 shows the TCR alpha chain sequence of CTL 1A.1/506

METLLGPLILWLQLQWVSSKQEVTQIPAALSVPEGENLVLNCSFTDSAIYNLQWFRQDPGKGLTSLLLIQSSQREQTSGRLNASLDKSSGRSTLYIAASQSGDSATYLCAVGGNDYKLSFGAGTTVTVRANIQNSDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESSCDVKLVEKSFETDTNLNFQNLSVIGF RILLLKVAGFNLLMTLRLWSS

SEQ ID NO. 4 shows the TCR beta chain sequence of clone CTL 1A.1/506

MGTRLFFYVALCLLWTGHMDAGITQSPRHKVTETGTPVTLRCHQTENHRYMYWYRQDPGHGLRLIHYSYGVKDTDKGEVSDGYSVSRSKTEDFLLTLESATSSQTSVYFCAISEKLAGAYEQYFGPGTRLTVTEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQQGVLSATILYEILLGKATLYAVLVSALV LMAMVKRKDSRG

SEQ ID NO. 5 shows the TCR alpha chain sequence of clone CTL 2C/417

MASAPISMLAMLFTLSGLRAQSVAQPEDQVNVAEGNPLTVKCTYSVSGNPYLFWYVQYPNRGLQFLLKYITGDNLVKGSYGFEAEFNKSQTSFHLKKPSALVSDSALYFCAVRDMIEGGGNKLTFGTGTQLKVELNIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESSCDVKLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRLWSS

SEQ ID NO. 6 shows the TCR beta chain sequence of clone CTL 2C/417

MGIRLLCRVAFCFLAVGLVDVKVTQSSRYLVKRTGEKVFLECVQDMDHENMFWYRQDPGLGLRLIYFSYDVKMKEKGDIPEGYSVSREKKERFSLILESASTNQTSMYLCASSRQGAVGQPQHFGDGTRLSILEDLNKVFPPEVAVFEPSEAEISHTQKATLVCLATGFFPDHVELSWWVNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSVSYQQGVLSATILYEILLGKATLYAVLVSALV LMAMVKRKDF

SEQ ID NO. 7 shows the TCR alpha chain sequence of clone CTL 1A3/46

MSLSSLLKVVTASLWLGPGIAQKITQTQPGMFVQEKEAVTLDCTYDTSDPSYGLFWYKQPSSGEMIFLIYQGSYDQQNATEGRYSLNFQKARKSANLVISASQLGDSAMYFCAMRPHFGNEKLTFGTGTRLTIIPNIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKTVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESSCDVKLVEKSFETDTNLNFQNLSVIGFRILLLKVAGFNLLMTLRLWSS

SEQ ID NO. 8 shows the TCR beta chain sequence of clone CTL 1A3/46

MGTRLFFYVALCLLWTGHMDAGITQSPRHKVTETGTPVTLRCHQTENHRYMYWYRQDPGHGLRLIHYSYGVKDTDKGEVSDGYSVSRSKTEDFLLTLESATSSQTSVYFCAISEKLAGAYEQYFGPGTRLTVTEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVNGKEVHSGVSTDPQPLKEQPALNDSRYCLSSRLRVSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRADCGFTSESYQQGVLSATILYEILLGKATLYAVLVSALV LMAMVKRKDSRG*

SEQ ID NOs 9 to 26 show the CDR sequences of the TCR of the invention.

EXAMPLES Example 1 Generation of Melanoma-Reactive CD8 Positive T Cells

Out of the melanoma patient MA-MEL-86 four different permanent tumorcell lines (MA-MEL-86A, -86B, -86C, -86F) were established from separatelymph node metastases. Both MA-MEL-86B and MA-MEL-86F did not expressHLA I on their cellular surface due to a biallelic mutation in theβ2-microglobulin gene. The tumor cell line MA-MEL-86C lost one HLAhaplotype. In contrast thereto, the MA-MEL-86A line expressed all HLA Ialleles, but showed as the only one out of the four tumor cell lines noexpression of melanosomal differentiation antigens (FIG. 1).

Tumor-reactive CD8 positive T cells were generated in so called mixedlymphocyte-tumor cell culture (MLTC) by weekly stimulation oflymphocytes taken from peripheral blood mononuclear cells, PBMCs, withautologous tumor cell lines MA-MEL-86A or MA-MEL-86C. Surprisingly, theinventors recognized that MLTC-responder lymphocytes in varyingrecognition patterns still recognized the HLA I negative variantsMA-MEL-86B (FIG. 2) and MA-MEL-86F. This was confirmed with clonal Tcells (CTL) from these MLTCs. MLTCs and CTL clones were used for theidentification of their target molecules.

Example 2 Identification of CSF2RA

A cDNA library of the melanoma cell line MEL-86A constructed in theeukaryotic expression vector pcDNA3.1 was screened with responderlymphocytes of MLTC 1A.1. In a first step, cDNA pools consisting of 100cDNA clones were co-transfected with HLA I alleles of the patient into293T-cells. The transfectants were tested for recognition by the Tcells. One of the pools was fbund to be responsive. Subsequently, astep-by-step cDNA cloning was performed. In this way CSF2RA wasidentified as a target of the MLTC 1A.1 (FIG. 3). Then T cell cloneswere isolated which were able to detect the HLA I negative melanoma cellvariants and which were directed against CSF2RA. In particular whenlooking at the cross-reactivity of T cells against CSF2RA, onerecognizes the particularity of the antigen. The CSF2RA-reactive T cellswere able to detect 60% of the available melanoma cells lines, but alsotumor cell lines of pancreas, colon, lung, ovarian, gallbladder originas well as myeloid leukemias (Table 2).

TABLE 2 Allogeneic tumor lines recognized by the CSF2RA-reactive CTL1A.1/506. Analyzed tumor lines recognition/n tested Melanomas 12/20Pankreas carcinomas (PC) 2/2 Kidney carcinomas (RCC) 0/5 Acute myeloidLeukemias (AML)  5/13 Chronic myelogenous Leukemias (CML)  0/11Colorectal carcinomas (CRC) 1/6 Lung carcinomas 1/4 Breast carcinoma 0/1Ovarian carcinoma 1/1 Gallbladder carcinoma 1/1 Glioblastoma  0/11

On the other hand, all tested normal cell lines, amongst othersmelanocytes, granulocytes and monocytes, derived from peripheral blood,were not recognized by the CSF2RA-reactive T cells (see FIG. 4). Thepurity of the cell preparations were tested in advance via flowcytometry. Furthermore, subsequent to a transfection with CSF2RA, celllines from different species could be detected by the CSF2RA-reactive Tcells (see FIG. 5). A co-transfection with HLA I was not necessary.

Using flow cytometry the inventors furthermore showed that allCSF2RA-reactive T-cells were TCRαβ positive, CD3 positive and CD8positive, and expressed the T cell receptor beta chain Vβ12 (TRBV10-3).The reactivity of these T cells could only be inhibited by antibodiesagainst CD3 or CSF2RA, but not with antibodies against HLA I or II (seeFIG. 6). cDNAs of the alpha and the beta chain of the TCR of theHLA-independent CSF2RA-reactive T-cell clone 1A.1/506 were cloned andsequenced (see FIG. 7, SEQ ID No. 3 and 4).

Example 3 Identification of TRP-2

In panel test 40 cDNA clones which encode known melanoma-associatedantigens, were transfected into 293T cells. The transfectants weresubsequently tested for recognition by responder lymphocytes of MLTCs 1Cand 2C. It was fbund that both MLTCs and CTL clones derived thereofcould recognize the HLA I negative tumor cell lines MA-MEL-86B and -86Fand targeted the melanosomal differentiation antigen TRP-2. Theycross-reacted with any of the TRP-2-expressing melanoma cell linesavailable in the laboratory as well as with normal melanocytes,and—after transfection with TRP-2—also with non-melanocytic cells ofmouse, hamster and monkey origin (see FIG. 8). A co-transfection of HLAI molecules was not necessary. The HLA-independent TRP-2 reactive Tcells recognized also murine melanoma cells and murine TRP-2 aftertransfection.

Using flow cytometry the inventors furthermore showed that allTRP-2-reactive T cells were TCRαβ positive, CD3 positive and CD8positive, and expressed the T-cell receptor beta chain Vβ3 (TRBV28). Thereactivity of these T cells could only be inhibited by antibodiesagainst CD3, but not by antibodies against HLA I or II.

The direct recognition of TRP-2 by CD8 positive T cells would requirethe cell surface expression of the antigen. Indeed the inventors couldshow cell surface expression with a TRP-2 reactive antibody (see FIG.9). For a clear-cut evidence of TRP-2 on the surface of human melanomacells, the inventors used recombinant DNA technology to modify TRP-2with a 13 amino acid-long alpha-bungarotoxin recognition site. This siteis able to bind the neurotoxin alpha-BTX with high affinity andspecificity. Using alpha-BTX coupled to a fluorochrome, visualization ofthe TRP-2 fusion protein on the cell surface of transfectants becamepossible (see FIG. 10).

This result was further supported by the finding that a deletion of thetransmembrane domain (TMD) of TRP-2 resulted in a loss of therecognition by the T cells, which could be reversed by the substitutionwith an unrelated TMD of HLA-A*24:01 (see FIG. 11).

cDNAs of the alpha and the beta chain of the TCR of the HLA-independentTRP-2-reactive T-cell clone 2C/417 were cloned and their function wastested via transfer into CD8 positive T cells of PBMCs of a healthydonor (SEQ ID No. 5 and 6; FIG. 12).

Example 4 Cloning, Ectopic Expression and Functional Analysis of aSecond CSF2RA-specific a/b T Cell Receptor

The a- and b T cell receptor chain- (TCR-) cDNAs were isolated from theCSF2RA-specific CTL 1A.3/46 and cloned as a bicistronic construct into aretroviral vector (FIG. 13A). Subsequently, the human constant domainswere replaced by murine TCR-constant domains (“chimerized” or“murinized”) to minimize pairing of transduced with endogenousTCR-chains after ectopic expression in human T cells.

Cell surface expression of the CSF2RA-specific TCR in human T cellstransduced with the native (left) and the chimerized (right) constructsis shown in FIG. 13B. The percentage of TCR-Vb12-positive T cells inuntransduced PBMCs in this sample was <3% (not shown).

In a response analysis of the CSF2RA-reactive CTL 1A.3/44 in comparisonto CSF2RA-TCR-transduced allogeneic T cells CSF2RA-negative target cells(MA-MEL-86F and 293T) were not recognized while MA-MEL-86B cellsexpressing CSF2RA endogenously and 293T cells transfected with theantigen were recognized (FIG. 13C). T cells transduced with thechimerized TCR showed a response comparable to that of theCSF2RA-reactive CTL 1A.3/44 and significantly higher reactivity than Tcells transduced with the “native” TCR construct.

The invention claimed is:
 1. A T cell receptor (TCR), or a bindingfragment thereof, the TCR comprising: i) SEQ ID NO: 14, ii) SEQ ID NOs:12, 13, and 14, wherein the TCR is (i) a chimeric TCR, (ii) a γδ TCR,(iii) a binding fragment of a TCR, or (iv) a single chain TCR (scTCR).2. A pharmaceutical composition, comprising a TCR, or a binding fragmentthereof, according to claim 1; and a pharmaceutically acceptable carrieror diluent.